The calculated “time to temp” value is based on a scientific formula for heat input into a fixed mass of a carbon steel load, it does not consider the heat losses associated with thermal conduction, convection or radiation.

The “Calculated time + 50%” value is an approximation which artificially accounts for heat losses when pre-heating pipe, up to 52” OD (1320mm), up to 400°F (204°C) with insulation on the OD only.

Times will vary based on the area you are heating, insulation coverage and environmental conditions.

When heating very large surface areas at post weld heat treat temperatures, time to temperature will increase significantly due to increased heat losses. It is recommended to contact Miller for assistance.